[FIXED] how to find an array made by results of integrals

Issue

In my code res1 is the result of an integral. My goal is to repeat this integral for 1000 times (with for loop maybe but I can not figure out how) with one different variable which is :

Energy = np.arange(2.1,102.1,0.1)

so in the code below, E means energy but it is the first variable of that array. I want to have an array that is made of the results of the integrals ( by changin E like 2.1 to 2.2 and then to 2.3)

import numpy as np
from math import pi,sqrt
vtheta=np.linspace(0.0,pi,1000)
def f(theta):
    E=2.1
    val=(2.0)/np.sqrt(E-1+np.cos(theta))
    result=(val.sum()-(sqrt(1./2.1)+sqrt(1./298.)))*((np.pi-0)/999.)
    return result
res1=f(vtheta)

when I try to put the for loop in the function I change the inside of result which I do not want to do.

Solution

Something like this?

import numpy as np
import matplotlib.pyplot as plt

def f(theta, E=2.1):
    val = 2. / np.sqrt(E - 1 + np.cos(theta))
    return (val.sum() - np.sqrt(1. / 2.1) - np.sqrt(1. /298.)) * (np.pi / 999.)

vtheta = np.linspace(0., np.pi, 1000)
energies = np.arange(2.1, 102.1, .1)
results = []
for e in energies:
    results.append(f(vtheta, E=e))
    
plt.plot(energies, results)
plt.xlabel('Energy')
plt.show()

Gives you the following plot:

Answered By - asdf